Try to buy thick-skinned fruit; thinner skinned citrus fruits don’t have much to contribute to marmalade!
1 large orange
2 cups (500 mL) water
1 medium-small zucchini, coarsely grated (about 1 1/2 cups)
4 cups (1 L) sugar
Wash the lemons and orange well and grate the zest off using the coarse side of a box grater. Put it into a large saucepan with the water. Peel the white pith off the fruit and add to the pot (a few large chunks will be easy to remove) and bring to a boil; reduce heat and simmer for about half an hour. Meanwhile, finely chop the flesh of the lemons and orange, or pulse them in a food processor.
Remove the pith from the saucepan and add the lemon, orange and zucchini to the pot. Bring back to a boil and simmer for 20 minutes, then add the sugar and bring to a full boil. Cook, stirring occasionally, for 30 minutes. To test for the jelly stage, put a small bit in a small dish and put it in the freezer; you should be able to tell when it’s cold if it has turned to marmalade. If you want to use a candy thermometer, the temperature should reach 210F.
Pour into hot, clean jars; seal and cool.
Makes 4 cups, or 4 250 mL jars.